On 07/05/2025 6:26 am, Frediano Ziglio wrote:
> On Tue, May 6, 2025 at 11:17 PM Andrew Cooper <andrew.coop...@citrix.com>
> wrote:
>> On 06/05/2025 3:05 pm, Andrew Cooper wrote:
>>> On 06/05/2025 2:56 pm, Frediano Ziglio wrote:
>>>> diff --git a/xen/include/xen/sha2.h b/xen/include/xen/sha2.h
>>>> index 47d97fbf01..ea8bad67e4 100644
>>>> --- a/xen/include/xen/sha2.h
>>>> +++ b/xen/include/xen/sha2.h
>>>> @@ -9,6 +9,16 @@
>>>>
>>>> #define SHA2_256_DIGEST_SIZE 32
>>>>
>>>> +struct sha2_256_state {
>>>> + uint32_t state[SHA2_256_DIGEST_SIZE / sizeof(uint32_t)];
>>>> + uint8_t buf[64];
>>>> + size_t count; /* Byte count. */
>>>> +};
>>>> +
>>>> +void sha2_256_init(struct sha2_256_state *s);
>>>> +void sha2_256_update(struct sha2_256_state *s, const void *msg,
>>>> + size_t len);
>>>> +void sha2_256_final(struct sha2_256_state *s, void *_dst);
>>>> void sha2_256_digest(uint8_t digest[SHA2_256_DIGEST_SIZE],
>>>> const void *msg, size_t len);
>>> sha2_256_digest() is unlike the others as it holds sha2_256_state
>>> internally. I'd suggest having all of the additions below this point,
>>> which group them more nicely.
>>>
>>> Can fix on commit. Otherwise LGTM.
>> Not quite. Now that sha2_256_final() is exported, it should have a
>> proper type for _dst. I've folded:
>>
>> diff --git a/xen/include/xen/sha2.h b/xen/include/xen/sha2.h
>> index 0d55fe640431..cb30e8f8d77c 100644
>> --- a/xen/include/xen/sha2.h
>> +++ b/xen/include/xen/sha2.h
>> @@ -21,6 +21,7 @@ struct sha2_256_state {
>> void sha2_256_init(struct sha2_256_state *s);
>> void sha2_256_update(struct sha2_256_state *s, const void *msg,
>> size_t len);
>> -void sha2_256_final(struct sha2_256_state *s, void *_dst);
>> +void sha2_256_final(struct sha2_256_state *s,
>> + uint8_t digest[SHA2_256_DIGEST_SIZE]);
>>
>> #endif /* XEN_SHA2_H */
>> diff --git a/xen/lib/sha2-256.c b/xen/lib/sha2-256.c
>> index 896a257ed9b7..08ef7011a1c3 100644
>> --- a/xen/lib/sha2-256.c
>> +++ b/xen/lib/sha2-256.c
>> @@ -171,9 +171,9 @@ void sha2_256_update(struct sha2_256_state *s, const
>> void *msg,
>> memcpy(s->buf + partial, msg, len);
>> }
>>
>> -void sha2_256_final(struct sha2_256_state *s, void *_dst)
>> +void sha2_256_final(struct sha2_256_state *s, uint8_t
>> digest[SHA2_256_DIGEST_SIZE])
>> {
>> - uint32_t *dst = _dst;
>> + uint32_t *dst = (uint32_t *)digest;
> That is we are never going to support architectures with unaligned
> memory access.
Note how it's written to.
/* Store state in digest */
for ( i = 0; i < 8; i++ )
put_unaligned_be32(s->state[i], &dst[i]);
It works just fine on misaligned buffers.
~Andrew
